The present invention relates generally to keyboard apparatus for electronic musical instruments, such as electronic organs and electronic pianos.
With acoustic pianos, there is produced a key touch feeling called “let-off feeling” that, when a key has been depressed (i.e., static load has been applied to the key), the key touch temporarily becomes heavy (i.e., reactive force to the depressed key increases) partway through the key depression and then rapidly becomes light (i.e., the reactive force to the depressed key decreases) as the key is further depressed. Various schemes have been proposed to allow an electronic musical instrument keyboard apparatus to emulate such a let-off feeling. Japanese Patent No. 3458400, for example, discloses an electronic musical instrument keyboard apparatus, which includes hammers each not only pivoting in interlocked relation to movement of a corresponding key but also giving a feeling of mass during the key depression, and in which the rear end of the hammer contacts a roller that is supported by a resilient member. Immediately before the end of the key depression, the rear end of the hammer engages (or contacts) with the roller so that the reactive force to the depressed key increases by resistance of the resilient member. Upon end of the key depression, the rear end of the hammer disengages from the roller so that the reactive force to the depressed key rapidly decreases. In the aforementioned manner, a let-off feeling can be emulated.
In the aforementioned conventional keyboard apparatus, there can be achieved a left-off feeling, but, even at the time of key release, the reactive force to the depressed key would increase due to the engagement (or contact) between the hammer and the roller. Such increase of the reactive force at the time of the key release would retard a returning velocity of the key and thus adversely influence a successive key depression performance of the keyboard apparatus.